Not really a pocket money thing, but when mine were earning their own money, we used to incentivise savings by matching euro for euro if they were saving for something worthwhile. Did this right up to matching their deposit for property purchase.
Not a perfect system and open to "creative accounting" but it worked for us!
my son is 8 and he's getting 20/month for unloading the dishwasher. he earns it, understands savings and can work out how long he has to wait untill he can buy something he wants. I also show him alternatives, explaining pros and cons, e.g. buying cheaper online but waiting longer vs buying something now but paying more.
I give my early teenagers a tenner a week and their (no limit data etc) phone credit is paid for. I never got regular pocket money when I was their age (my parents were a bit behind the curve on this) and I always felt like a bit hard done by compared to my pals at school. I think its important for kids self-esteem that they've got something dependable coming to them weekly so they can plan purchases or a trip out etc.